Chances are your last half marathon wasn’t exactly 13.1 miles long. In fact, it’s likely your GPS said it was just a smidge over that: 13.4, perhaps, or maybe even more than 14 miles. It happens – a lot. By that logic, then, most courses are measured inaccurately…right?
Avoid putting too much stock in what your GPS watch says, cautions coach Mario Fraioli, founder of The Morning Shakeout newsletter and podcast. A myriad of variables can throw off your GPS reading, such as weather, poor satellite connection or tall buildings.
“I’ve literally watched people run a mile on a track and the GPS will beep in the middle of the final straightaway. The person told me that the track was ‘off.’ I just shake my head. The GPS watch isn’t helping these folks.”
Besides, the course is measured – multiple times – says Ted Metellus, Director of Course Operations for the Rock ‘n’ Roll Marathon Series. “All of our courses are measured by a certified member of USA Track & Field. In fact, each route is measured at least three times to verify its accuracy.”
So what gives? It’s all about the measurement tool. While everyone today runs with watches that utilize a satellite in the sky, course measurements are physically on the ground. Each mile marker is confirmed to the exact distance with the use of Jones Counter, a measurement device placed on the front wheel of a bicycle. As the bicycle travels the length of the course, the Jones Counter records the revolutions of the wheel.
The use of the Jones Counter explains another big reason why your race is seemingly longer: The bike always takes the shortest, straightest route. You probably don’t. That one factor can help you shave distance (and time) off your race.
“Learn what a tangent is and teach yourself how to run in a straight line,” says Fraioli. “Follow the line that’s closest to the turn to run the shortest distance possible when going around a corner. Also, avoid bobbing and weaving around other runners, as this will cost you time and energy.”
You may think you’re following the measured course by running to the right-hand side of the road, but it’s likely the course was actually measured on the middle or even left-hand side – especially on the corners. So long as the road is open to you, take the tangent. It’s one of the few times we’ll ever advise you to cut corners as a runner.